This study is a component of a multi-center, double-blind, parallel clinical safety study. It will test the tolerances and efficacy of the thromboxane receptor antagonist, Ifetroban. Evidence clearly suggests that the production of thromboxane may play a role in the baso-spastic element of claudication. Using a standardized exercise protocol over twelve weeks, Ifetroban's effects will be evaluated at three different doses. The expected outcome is improved claudication time.